Cr‐site preference of BaFe_12–xCr_xO₁₉ hexaferrite ceramics monitored by Mössbauer spectroscopy

Abstract

PACS 61.10 Nz, 75.50. Gg, 75.60.Ej, 76.80.+y Site preference of Cr in the M-type barium ferrite ceramics was monitored by powder X-ray diffraction (XRD), magnetization measurements and Mössbauer spectroscopy. The calcined BaFe 12-x Cr x O 19 powders (x = 0.0 -0.8) obtained by the sol gel method were die-pressed into pellets and then sintered at 1300 °C in a oxygen atmosphere for 12 hrs. All the phases of the ceramics were of the pure magnetoplumbite structure. The saturation magnetization (M s ) is found to be a function of Cr ion content. The M S of the ceramics decreases due to the dilution of the magnetic interaction with increasing Cr concentration. The coercivity (H c ) of the ceramics increases due to finer grain observed by scanning electron microscopy (SEM). Fitted Mössbauer spectra show that Cr ions preferentially occupy into the 2a, 12k and 4 f 2 Fe crystallographic sites.

Optical and Multiferroic Properties of Gd‐Co Substituted Barium Hexaferrite

“…In the recent past, barium hexaferrite (BaM) has been center of keen interest due to its applications in microwave absorbing at Gigahertz frequency, magnetic recording and multi-layer chip inductors as surface mounting for miniature circuit devices. [1][2][3] Barium hexaferrite magnetic and dielectric properties are playing important role in multichip layer inductor where ferrite layer get interweaved with suitable conductor. It is well established fact, physical properties of barium hexaferrite can be tailored by substituting different ions like Ti-Ru, Ni-Ti, Al, Co-Zr, Ga, Co-Ti, Mn-Mo, Cr, Zr-Zn, Co-Sn, Ni-Ru, Sc and Co-Ti for Ba ++ and Fe +++ .…”

Colored oxides with hibonite structure II: Structural and optical properties of CaAl12O19-type pigments with chromophores based on Fe, Mn, Cr and Cu

“…Solution combustion synthesis using metal nitrates was performed [25,32,50]. Powder samples were made through wet techniques: sol-gel [8,21] and hydrolysis of alkoxydes followed by thermal decomposition and reaction [8]. However, low temperature synthesis techniques are not always applicable for synthesis of hibonite phases because most of them require fairly high synthetic temperatures (above 1300 o C).…”

“…Spectroscopic investigations (absorbance and fluorescence spectra) [4,6,7,34,42,55], nearinfrared (IR) spectra [7,37], emission spectra [9], luminescence [10], color description by L*a*b* parameters [53][54][55] and other optical property characterizations [34,35,41,43,50,51,[53][54][55] were employed. Additional information of the hibonite-based oxides was collected using electron paramagnetic resonance (EPR) [7], Mössbauer technique [4,35,38,40,[42][43], magnetic susceptibility measurements [6,21,56] magnetic structure refinement [19,29,33,47], thermal analysis [33,55], along with measurements of electrical properties [24,25], dielectric properties [56] chemical reactivity [43] and microhardness [43,47].…”

“…X-ray [16][17][18] and neutron diffraction [19] were applied to refine the structures of CaFe 6 Al 6 O 19 [16], SrAl x Fe 12-x O 19 [17,18] and BaFe 12-x Mn x O 19 [19] phases. The distribution of Mn and Fe ions in BaFe 12-x Mn x O 19 [20], the site preference of Cr in BaFe 12-x Cr x O 19 [21], the arrangement of Ti and Mn ions in BaTiMnFe 10 O 19 [22] and Fe ions in SrAl x Fe 12-x O 19 [23] were also determined with diffraction methods. Structural, electrical and magnetic properties of CaCr x Fe 12-x O 19 (x = 3, 4, 8, 9) [24] and CaFe 12-x Al x O 19 (x = 3, x = 4) [25] as well as relaxor-like improper ferroelectricity in PbFe 6 Ga 6 O 19 were studied [26].…”

Microstructure and magnetic properties of Al-doped barium ferrite with sodium citrate as chelate agent

“…The crystal structure of BaM can be described as a stacking sequence of the basic blocks RSR n S n where the R contains a two O 4 -layer block and one BaO 3 with composition (Ba 2 þ Fe 6 3 þ O 11 2 À ), and S is a block with two O 4 -layer with composition Fe 6 3 þ O 8 2 À . The asterisk means that the corresponding block is turned 1801 around the c-axis [7]. In addition, it is well known that the Fe 3 þ ions distributed on 12k, 2a and 2b sites have up-spin electron configuration, while those located on 4f1 and 4f2 are spin down.…”